Fluorescence Performance Of Fe³⁺ Ion Modified 1,8-naphthalic Anhydride/mesopores SiO₂ And Preliminary Study On Drug Release

Much attention has been paid to the drug sustained-release system loaded on the modified silica materials since it was reported for the first during 2001,and many aspects including the controlled dispersion of surface,modification of mesoporous matrix andrelease behavious havediscussed in-depth.Althoughmany researchesshow that mesoporous silica could be promising substrates for the hosting and release of a large variety of drug molecules,yet it is difficult to detect the right position of drugs and the certain time of its release behavious in vivo.Therefore,the organic-inorganic hybrid mesoporous materials were synthesized with grafted luminescent materials onto mesoporous silica as a host in order to take the advantage of its potential applications in drug delivery fields.In recent years,with the development of nanoparticle synthesis chemistry,various kinds of nano-mesoporous luminescent materials with different composition,structure and luminescent properties were studied and widely applied in various fields.However,the results presented that several problems of organic luminescent material such as weak light intensity,low quantum yield and quench,needs a proper solution for their applicability.Keeping the above mentioned problems in mind and on the basis of our preliminary work,metal ion(Fe³⁺)has been selected to modify 1,8-naphthalic anhydride?NA?.For this purpose,a series of organic-inorganic hybrid mesoporous luminescent materials were synthesized which improved the luminescent properties of NA.Moreover,it is very beneficial for potential applications in the fields of drug sustained/controlled delivery.The structure,micro-morphology,composition and luminescent performance of resultant samples were characterized using XRD,N₂ adsorption-desorption isotherms,TEM,SEM,FT-IR,TGA,ICP-OES,PL,and Time-resolved fluorescence measurements techniques,especially SAXS method was employed to characterize the fractal structure of organic-modified mesoporous BMMs in order to further elucidate the formation of surface features and derivation of mass fractal.Moreover,the interaction between metal ion and chromophores explained via modification mechanism was investigated in detail and the results obtained are as follows:?1?The best modified anion was obtained by modifying NA with different anions of iron salts(NO^3-,Cl^-,C₆H₅O₇^3-).The structure and fluorescence properties of the obtained FX-NA were characterized to study the interaction between anions and NA,and the effect of anions on its fluorescence properties.The results showed that the stronger binding force of Fe³⁺and Cl^-can inhibit the attraction of Fe³⁺ions to NA molecules compared with the other two anions,which is the reason for the smaller blue shift of FC-NA.?2?The FC-NA complex was synthesized by modifying NA with Fe Cl₃ as modifier.And the effect of Fe Cl₃ on the fluorescence properties of FC-NA was studied.The results showed that with the increasing amont of Fe³⁺,the characteristic peaks occurred to red shift after blue shift.The introduction of Fe³⁺mainly leads to the uneven distribution of electron cloud density of NA,and the other reason may be due to the agglomeration of FC-NA with the increase of Fe³⁺ions.?3?The fluorescence properties of FC-NA in different solvents?acetone,acetonitrile,DMF,DMSO?and the influence of solvent polarity were studied.It can be seen that the red shift of the emission peak from 375 nm to 380 nm is due to the increase in solvent polarity?acetone<methanol<DMF<acetonitrile<DMSO?.?4?The effects of different concentrations on the fluorescence properties and dispersion behavior of FC-NA were studied with acetone as solvent.Experiments show that the presence of FC-NA at low concentrations is monodisperse and,conversely,agglomerates at high concentrations.?5?The effect of different FC-NA loading on the fluorescence properties of FC-NA@BMMs was studied by changing the loading of FC-NA.The results show that when the mass ratio of FC-NA and APTES-BMMs exceeds 0.2,the effect of the mesopore domain becomes obvious.On the other hand,the surface effect becomes obvious,which may be related to the rigidity of the microenvironment of FC-NA@BMMs related.?6?To research FC-NA@BMMs drug loading and release and its fluorescence properties.The results show that IBU is agglomerated in the Fe-NA@BMMs-0.2channel.And with the release,the samples still maintain strong fluorescence intensity,indicating that Fe-NA@BMMs-0.2 can be drug-loaded,but also in the release while maintaining a good fluorescence intensity.